Embodiments of the present invention relate to an automated test equipment for testing a device under test. Further embodiments of the present invention relate to a method for testing a device under test.
The cost of test is a critical economic aspect for semiconductor manufacturers and semiconductor test companies (test houses) and thus a key competitive value for automated test equipment (ATE). The cost of electrical energy is becoming an increasingly important portion of the overall test costs, since integrated semiconductor devices (IC) increase in speed, transistor count and system complexity with the constant achievements of modern semiconductor technology. The consequence is a similarly growing demand in speed, accuracy and parallelism combined with a demand for more flexibility and broader application coverage for testing these ICs on ATE. Such a demand is currently satisfied at the expense of a significant increase in power consumption for operating ATE and its related infrastructure.
The competitive operation of a test floor containing many ATE is only possible when the equipment can be adapted quickly to a large portfolio of devices and applications. Therefore ATE necessitates the presence of a flexible pool of many configurable tester subunits. With respect to the time critical management of production the stability of ATE on a test floor in terms of functionality and accuracy is essential. In the past the stability was ensured by keeping ATE powered all the time with all its resources and infrastructure fully active, resulting in a growing cost for the electrical energy supplied to the ATE. In addition, the thermal management system of ATE also shows increasing thermal output energy to maintain stable temperature conditions for precise operation. This energy in turn needs to be transported out of the production building spending additional energy. Therefore a growing amount of energy consumption is observed for the air conditioning of the test floor buildings and the heat exchangers of global cooling units on the production plants. This energy also contributes to a constantly growing cost of test.
Also in those countries where mass production of semiconductors is predominantly found, an increasing consciousness for environmental protection is emerging, particularly in the presence of the global warming discussion all over the world. Therefore it can be observed that the decision on what production equipment is used/purchased is more and more influenced by governmental programs and local legislation aiming at a transition to more environmentally compatible, but also more costly ways of producing electrical energy as well as by the higher energy taxes. This means that the more and more inevitable use of so called “green” energy will be an additional driver for higher cost of test even in Asian production sites. The reaction of the semiconductor industry is therefore a much stronger focus to low energy consumption of manufacturing equipment than what we saw in the past.
A more consumption-aware power control is further justified by frequently occurring stability issues in the power supply network of a production environment. The energy capacity of the supply network is often close to the limits and overload situations can't be resolved quickly when the equipment constantly maintains its full power demand.
Hence, there is a need for a reduction of the power consumption of an automated test equipment which would help to avoid or to recover front overload situations and therefore would help to both stabilize production and to increase the MTBF (mean time between failure) of an automated test equipment.